Refrigerator cabinets and insulation thereof



March 15, 1966 c. H. WURTZ REFRIGERATOR CABINETS AND INSULATION THEREOFOriginal Filed March 9. 1964 2 Sheets-$heet 1 INVENTOR. Clifford H.Wurfz Fig.

H119 Affom ey March 15, 1966 c. H. WURTZ REFRIGERATOR CABINETS ANDINSULATION THEREOF 2 Sheets-Sheet 2:

Original Filed March 9. 1964 INVENTOR. U/iffard H. Wurfz H119 Afro/nayUnited States Patent Office Continuation of application Ser. No.350,468, Mar. 9, 1964. This application May 4, 1964, Ser. No.

3 Claims. 01. 62-273) This application is a continuation of myco-pending application Serial No. 350,468 filed March 9, 1964, nowabandoned.

This invention pertains to refrigerating apparatus and more particularlyto refrigerator cabinets and the insulation thereof.

When a substantially rigid or semi-rigid foam type insulation is usedfor refrigerator cabinets, because of this rigidity there is difficultyin removing parts of the refrigerator and particularly parts of therefrigerating system which are located in or alongside the insulationfrom the cabinet for inspection or repair. Patent 3,078,003 does show anarrangement in which a polyethylene sheeting surrounds an inner linerfor preventing adherence of the foam insulation to the inner liner, butunless a tapered arrangement is used there is a possibility of bindingbetween the foam and the liner. Also, this arrangement does not allowremoval where the part to be removed, such as an evaporator, has anirregular surface. Any irregularities of the part to be removed may beinterlocked with the foam or the foam may have obstructions thereonwhich obstruct the removal of the part through interference withprojections on the part.

It is therefore an object of this invention to provide an efficientinsulating arrangement in which rigid or semirigid foam insulation canbe efficiently used which provides for the easy removal of parts of therefrigerating system such as the evaporator from the cabinet without anypossibility of binding.

It is another object of this invention to provide an insulatingarrangement for a refrigerator cabinet which surrounds the evaporatorwith slab foamed insulation of high insulating value which provides forthe convenient removal of the evaporator without damaging the foaminsulation.

The penetration of moisture into the insulation spaces of refrigeratedcabinets has always been a difficult problem because it is difficult andpractically impossible to provide a perfect seal or a seal which willkeep moisture vapor out of the insulation space. The solution most oftenused is to attempt to seal the outer walls as completely as possible andto allow the inner walls to leak. However, this arrangement stillpermits moisture from the interior of the refrigerator cabinet topenetrate the insulation spaces. Where a sufficiently cold surface isexposed in the insulation space, the moisture vapor will condense to aliquid and depending on temperature will freeze thereon and then becomea problem when the refrigerator is defrosted or shut down.

Where a cold surface vulnerable to corrosion, such as aluminum, iscontacted by insulation in the insulation space, which may contribute toits corrosion this penetration of moisture may cause corrosion of thealuminum surfaces according to the corrosive contribution or action ofthe insulation. This may occur when polyurethane foam of especially highinsulating value, such as when blown by a halohydrocarbon gas, is incontact with the cold aluminum surface. The halohydrocarbon may adhereto the surface and in the presence of the moisture vapor and thealuminum may form a halogen acid with the aluminum apparently acting asa catalyst. The halo- 3,24%,h2h Eatented Mar. I5, 1956 gen acid such ashydrochloric, if formed, attacks and severely corrodes the aluminum.Where the aluminum forms a refrigerant evaporator container, andespecially Where the aluminum has been stretched in the roll bondingprocess, this corrosion may be sufficiently deep to cause leakage.

It is another object of this invention to provide an insulatingarrangement for a refrigerator cabinet which provides a corrosionpreventing barrier between the insulation and the freezing surfaceexposed in the insulation space.

It is another object of this invention to provide an insulatingarrangement for a refrigerator cabinet which surrounds the evaporatorwith slab foam insulation of high insulating value and especiallyminimizes the freezing of moisture between the foam insulating slabs andthe freezing surfaces of the evaporator exposed in the insulation spaceand provides for the removal and escape of the frozen moisture upondefrosting and melting.

These and other objects are attained in the form shown in the drawingsin which the outer sheet metal shell is provided with insulation in theform of glass fibers around the lower portion of the sides, back, andbottom surrounding the sheet metal inner liner of the above freezingcompartment. To provide superior insulation. for the below freezingcompartment, foam insulation slabs are provided for the upper portion ofthe back, side and top walls. The below freezing compartment is enclosedby a boxshaped sheet metal evaporator which is made readily insertableand removable inside of the foam insulation slabs by being surrounded bybags of flexible plastic resin sheet containing a layer of glass fiberinsulation. The flexibility and resiliency of the bags of glass fiberinsulation facilitates the ready insertion and removal of the sheetmetal evaporator. The bags containing the glass fiber insulation alsoserve to prevent corrosion between the foam slabs and the outer surfaceof the sheet metal evaporator when moisture penetrates the insulationspace. Any moisture freezing on the outer surface of the evaporatorwhich melts during the defrost period will be permitted to drain by thebags of glass fiber insulation through a suitable drainage system..

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIGURE 1 is a front view of a two-compartment refrigerator embodying oneform of my invention.

FIGURE 2 is a fragmentary vertical sectional view taken along the line2-2 of FIGURE 1 and FIGURE 3 is a fragmentary vertical sectional viewtaken along the line 33 of FIGURE 2.

Referring now more particularly to the drawings, there is shown inFIGURE 1 a two-compartment refrigerator cabinet 20 having an upper belowfreezing compartment 22 and a lower above freezing compartment 24 whichare closed respectively by the upper and lower doors 26 and 28. Therefrigerator includes an outer metal shell 30 provided with side walls32, a top wall 34, and a back wall 36.

In the assembly of the refrigerator cabinet, insulation is first placedon the bottom and the lower portions of the side and back walls. Thisinsulation may be in the form of bats 38 of glass fibers. After this,the box-shaped inner liner 40 may be inserted into the cabinet. A slab42 of polyurethane foam is then placed against the rear wall 36 abovethe rear bat of glass fiber insulation 38 as shown in FIGURE 2. In frontof this bat 42 is placed a sealed bag 44 containing a layer 46 of glassfiber insulation. This bag 44- may be made of any suitable plastic resinsuch as polyethylene, polyvinylidenechloride or copolymers ofvinylchloride and other suitable resins. This bag 44 containing thelayer of fiber glass insulation 46 extends substantially from the top ofthe bat of glass fiber insulation 38 to the top wall 34 of the cabinetsubstantially coextensive with the front face of the slab 42.

On top of the inner liner 40 there is placed a slab 48 of a polystyrenefoam insulation. This slab 48 does not have as high an insulating valueas the slab 42 but it does not have any possibility of corrosion likethe slab 42. The slab 48 is not required to have as high an insulatingvalue since it merely serves as a barrier between the below freezingcompartment 22 and the above freezing compartment 24. This slab 48 mayhave passages leading to a drain trough 50 formed around the upper edgesof the inner liner 40. This drain trough 50 may have one or more drainholes 52 draining into the interior of the liner 40 in the compartment24 for disposal. If desired, a bag similar to the bag 44 containingglass fiber insulation may be substituted for the slab 48. Also, ifdesired, a slab of polyurethane foam similar to the slab 42 may beplaced beneath such a substituted bag.

At the sides above the glass fiber insulation 38 are provided slabs 54of polyurethane foam. Resting upon top of these slabs 54 is a slab 56 ofsimilar polyurethane foam coextensive with the top wall 34. Thepolyurethane foam used for the slabs 42, 54, and 56 is preferably blownby a halogen substituted hydrocarbon such as trichioromonofluoromethaneor dichloridifluoromethane. The halogen substituted hydrocarbon issubstantially permanently retained in the cells of the polyurethane foamproviding superior insulating qualities. After this the sheet metalevaporator 58, covered by a sealed polyethylene bag 60 containing alayer 62 of glass fiber insulation extending across the top and down thesides, is introduced into the space between the slabs 48, 56, and theslabs 54. The evaporator 58 may be similar to the evaporator shown inPatents Nos. 2,712,726 issued July 12, 1955 or 2,863,303 issued Dec. 9,1958. The glass fiber insulation 62 has sufficient resiliency to pressagainst the slabs 54 and 56 tohold them against the outer shell 30 so asto minimize the occurrence of voids in the insulation. The sealed bag 60may be taped to the evaporator 58 during the installation. However, thistape may be later removed. The evaporator 58 is preferably made of rollbonded aluminum expanded to provide refrigerant passages and isconnected by refrigerant tubing 64 with a refrigerated plate 66 in theabove freezing compartment 24. The plate 66 is connected in series withthe avaporator 58 in a system such as is more fully described in PatentNo. 2,672,027 issued Mar. 16, 1954.

A strip 68 of glass fiber insulation is located in front of the slabs 54and 56 as shown in FIGURE 2. This may be inserted prior to the insertionof the slabs 54 and 56. The assembly of the cabinet is completed by theinstallation of the breaker strips '70 at the front of the belowfreezing compartment 22 and the installation of the breaker strips 72 atthe front of the above freezing compartment 24. Between the breakerstrips 70 and 72 there is provided a piece 74 of molded polyurethanefoam insulation, at the front of which there is provided a trim strip'76. In this cabinet the sealed bags 44 and 60 containing each a layerof glass fiber insulation effectively prevent contact between the slabs42, 54, and 56 of polyurethane foam insulation with the evaporator 58 sothat corrosion of the outer surface in the evaporator 58 is prevented.The sealed bag 44 extends outwardly between the slab 42 and the 54 and56 to the outer shell 30 to prevent a void or open space in theinsulation. The outer shell 30 is preferably sealed against thepenetration of moisture from the outside so that only the more dry airwithin the cabinet is permitted to leak into the insulation spacessurrounding the evaporator 58 and the inner liner 40. The moisture vaporpenetrating the insulation spaces will pass only very slowly through thefoam insulation slabs and the sealed bags 44 and 60 to the outer surfaceof the evaporator 58. Because the bags 44 and 60 are pressed against theouter surface of the evaporator 58 and its back wall 78, very littlemoisture can freeze onto these surfaces.

Any moisture which does freeze onto these surfaces will melt during ashutdown of the refrigerator. The inner liner 40 adjacent its upper sideand rear edges is provided with an upwardly and outwardly extendingflange 53 beneath the bottoms of the sealed bags forming a drain lip.This melted ice or frost will run down the outer surface of these bagsonto the flange 53 and thence to the trough 50 and be drained throughthe aperture 52 into the interior of the compartment 24 for disposal.Through this arrangement the below freezing compartment can be providedwith a superior insulation Without the danger of serious corrosion orwater logging of the insulation. By preventing interference andinterlocking between the foam slabs 54, 56 and the evaporator 58, theflexible sealed bags 44 and 60 also make it possible for the evaporator58 to be readily removed without any binding. The sealed bag 44 hassufficient resiliency to cover any projecting refrigerant conduits suchas the conduit and the accumulator 82 and to prevent any interferencewith the removal of the evaporator 58. Normally the sealed bag 60 willbe removed along with the evaporator 58 after the removal of the breakerstrips 70.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. A refrigerator including a cabinet having outer walls, slabs of foaminsulation lining said outer walls, a metal container located withinsaid outer walls, means for cooling said metal container, means forpreventing the corrosion of said container by said foam insulation andfor holding said slabs of insulation against said outer walls comprisinga thin flexible walled sealed bag of plastic resin containing throughouta layer of fibrous resilient insulating material extending between saidcontainer and said slabs having sufiicient resiliency to hold said slabsagainst said outer walls.

2. A refrigerator including a cabinet having outer walls, a removablemetal container within said outer walls, means for cooling saidcontainer below water freezing temperatures, slabs of foam insulationbetween said metal container and said outer walls, and means providingfor easy removal of said container without binding comprising removableresilient means for separating said slabs and said containerconstituting thin flexible walled sealed bag means of plastic resincontaining a layer of resilient fibrous insulating material extendingover the top and sides of said container having sufficient resiliency tohold said slabs against said outer Walls for minimizing the panetrationof moisture onto said container.

3. A refrigerator including a cabinet having outer walls, a lowercontainer located within said walls, a slab of polystyrene foam restingon top of said lower container, fibrous insulating material locatedbetween the sides of said lower container and the outer walls, aremovable upper metal container located above said slab of polystyrenefoam, means for cooling said upper container below water freezingtemperatures, slabs of polyurethane foam insulation extending above saidfibrous insulating material between the sides and top of said uppercontainer and said outer walls comprising a top slab resting upon thetops of said side slabs, removable resilient means for separating saidslabs of polyurethane foam insulation and said upper container forpreventing binding therebetween comprising thin flexible walled sealedbag means of plastic resin containing a layer of resilient fibrousinsulating material extending over the top and sides of said uppercontainer between said upper container and said slabs having sufiicientresiliency to hold said slabs of polyurethane foam against said outerWalls.

References Cited by the Examiner UNITED STATES PATENTS 2,432,042 12/1947Richard 62273 2,672,030 3/1954 Schweller 62-273 6 2,724,241 11/1955Jacobs 62273 X 2,739,456 3/1956 Saunders 62228 2,779,066 1/1957 Gaugleret a1. 52406 FOREIGN PATENTS 796,202 6/ 1958 Great Britain.

MEYER PERLIN, Primary Examiner.

LLOYD L, KING, ROBERT A. OLEARY, Examiners.

1. A REFRIGERATOR INCLUDING A CABINET HAVING OUTER WALLS, SLABS OF FOAMINSULATION LINING SAID OUTER WALLS, A METAL CONTAINER LOCATED WITHINSAID OUTER WALLS, MEANS FOR COOLING SAID METAL CONTAINER, MEANS FORPREVENTING THE CORROSION OF SAID CONTAINER BY SAID FOAM INSULATION ANDFOR HOLDING SAID SLABS OF INSULATION AGAINST SAID OUTER WALLS COMPRISINGA THIN FLEXIBLE WALLED SEALED BAG OF PLASTIC RESIN CONTAINING THROUGHOUTA LAYER OF FIBROUS RESILIENT INSULATING MATERIAL EXTENDING BETWEEN SAIDCONTAINER AND SAID SLABS HAVING SUFFICIENT RESILIENCY TO HOLD SAID SLABSAGAINST SAID OUTER WALLS.